This invention relates to novel processes for the resolution of racemic or optically enriched 2-benzyl-4-piperidone succinic acid, which has the chemical formula ##STR1## The (2R)-enantiomer of 2-benzyl-4-piperidone-succinic acid, which has the absolute stereochemistry depicted below, ##STR2## is an intermediate in the synthesis of a compound having the formula ##STR3## The above compound of formula I exhibits the ability to inhibit the angiotensinogencleaving activity of renin and is useful in the treatment of hypertension and congestive heart failure. Such compound and related peptides that exhibit activity as renin inhibitors are referred to in European Patent Application EP 0438233A2, published on Jul. 24, 1991. The aforesaid publication, is incorporated herein by reference in its entirety.
Methods by which (2R)-2-benzyl-4-piperidone-succinic acid can be converted into the above compound of formula I and related peptides that exhibit activity as renin inhibitors are described in Published European Patent Application EP 0438233A2, referred to above.
Harada et al., J. Org. Chem., 55, 1679-1682 (1990) refer to a method of preparing (2R)-2-benzyl-4-morpholine-succinic acid, which has the chemical formula ##STR4## by reacting the corresponding racemic compound with (S)-methyl mandelate, separating the resulting diastereomeric esters, and then hydrolyzing the ester having the "2R" configuration. They also report that attempts to resolve 2-benzyl-4-morpholinosuccinic acid with a wide range of chiral amines were unsuccessful.